Pentax's M-series telezoom — a manual-focus 80-200mm f/4.5 with a constant aperture.
The SMC Pentax-M 80-200mm f/4.5 is a telephoto zoom for the Pentax K bayonet mount, from the M-series generation designed to be compact alongside Pentax's smaller bodies. It offered a useful telephoto range with a constant maximum aperture.
This is a manual-focus lens with an 80-200mm zoom range and a constant maximum aperture of f/4.5 across that range. It carries Super Multi Coating. Exact construction and filter thread should be confirmed against the specific sample rather than assumed.
The 80-200mm span covers short to medium telephoto, suiting portraits, travel, casual sport and daylight wildlife. The constant f/4.5 aperture keeps exposure steady through the zoom and is bright enough for general outdoor work.
Constant-aperture M-series telezooms are affordable and reasonably compact, making them practical adapting lenses. Test the zoom and focus for smooth travel and any creep, inspect for haze, dust and fungus down the barrel, and confirm the aperture is dry. It fits Pentax K digital bodies and adapts to mirrorless.